As Sudan's feared Janjaweed militia step up their cross-border attacks into Chad, there is worrying new evidence that some Chadians have joined forces with the Janjaweed to attack their own countrymen.

Victims of attacks say that some Chadians are acting as "guides" to the Janjaweed, directing them to certain villages and suggesting which cattle to steal.

Many victims also say that some Chadians are taking part in the actual
killings.

An estimated 50,000 Chadian civilians have been displaced by the upsurge in Janjaweed attacks.

Dozens of villages along the Chad-Sudan border now lie empty as residents, terrorised by repeated incursions from Sudanese militia, have fled their homes.

The Janjaweed are accused of carrying out the worst atrocities against black Africans during the conflict in Darfur, just over the border into Sudan.

"We had just finished praying when the Janjaweed arrived on horseback," recalled Abdulaye Yaya Abdulaye, 40 - a survivor of the now-notorious Janjaweed massacre in the village of Djawara in April, in which 118 men died.

"There were many Chadians with them. The Janjaweed were wearing military fatigues, but the Chadians were in civilian clothing. Every man was armed.

"The Janjaweed carried Kalashnikovs and M14s. The Chadians also had arms, but carried machetes as well. After people were shot, if they were still alive, they were finished off with machetes."

Exactly why Chadians would want to join forces with Sudanese militia is
unclear.

Many people here talk about an "Arab alliance", where Arab Janjaweed from Sudan are teaming up with certain groups in Chad to attack non-Arab communities.

Political

Observers are wary of jumping to conclusions about ethnic cleansing, however - after all, several non-Arab groups have been persuaded to join this "Arab alliance".

Instead, the prime motivation appears to be political.

They take our cattle, kill men, even rape women

Aze Hamat, 23

The Sultan of this region, Seid Ibrahim Mustafa, says there is a strong link between Khartoum-backed Janjaweed militia and the Chadian rebels - who he suspects are also involved in the recent violence.

"The Janjaweed have a relationship with the Chadian rebels, and they are working for the Sudanese government," he says.

"Sudan wants to destabilise Chad. Why? We have the same tribes living on the both sides of this border.

"They [Khartoum] carried out a civil war in Sudan, and little by little, they are now coming deep into our country."

The theory is that some civilians in this area have been persuaded to join this alliance, either through coercion, or the promise of a share in the wealth as cattle are stolen and villages looted.

There are signs that the ultimate goal of this alliance may to be to overthrow Chad's President Idriss Deby Itno.

"Well before the attack, the Janjaweed visited us and asked us to join
their alliance, to help overthrow President Deby," explained another survivor of the Djawara massacre, which took place on the same day Chadian rebels attacked the capital, N'Djamena.

"We said no, we are just peasants, we cannot meddle in politics. So they said: 'Ok, if you don't want to join us, you will see what will happen'.

"A few weeks later, they came back to kill us."

High price

Many displaced Chadians are from the non-Arab Dajo ethnic group, whose members say that after refusing to join the alliance, they have been systematically targeted by Janjaweed.

The Dajo, who live along the Chad-Sudan border region, provided accommodation to Sudanese refugees when the Darfur conflict began three years ago.

Abdulaye Yaya Abdulaye says machetes like this were used to kill villagers

Some people believe they are now being attacked by the Janjaweed as revenge for having helped their Sudanese neighbours in the past.

As is often the case in such conflicts, the humanitarian price is high.

Many of the displaced, who are camping on the outskirts of Sudanese refugee camps for security, have little access to food, clean water or shelter.

The displaced Chadians tell very similar stories to their Sudanese refugee neighbours.

"There is no security," said Aze Hamat, 23, who lost her father and
two brothers in an attack.

"They take our cattle, kill men, even rape women," she said.

"If they find a pretty woman they will take her across the border, where she is raped. Sometimes the women are dumped back in the bush afterwards. Sometimes they are never seen again."